ML131396961

Age

Not specified

Sex

Not specified

Observation details

Continuing bird, seen periodically for the past week or so. Bird arrived with a large number of Herring Gulls around 9:30am. Herring Gull-sized with slate gray back, about the same color as a typical Lesser Black-backed Gull, of which there were at least 8 present by the time I left. In direct comparison, larger than Lesser Black-backed, larger and less attenuated body, and larger headed. Yellow bill with more or less straight edges, red gonydeal spot. Dark streaking throughout head and nape, slightly darker area surrounding the eye, pale iris. Very large and obvious tertial crescent at rest, and abnormally large white spot at terminus of P10, which together with the tertial crescent gave the bird an extensively white rear end at rest. There was almost no black whatsoever near the tip of P10, just a very small smudge visible in photos. The bird was not seen in flight, but did flap a few times while preening on the water. In spread wings, small white tongue tips were visible on P6 and P7 at least, and apparently also very limited on P8 (the “string of pearls”). P9 was dark throughout except at the tip, and P10 as stated was extensively white at the tip. On the underside of the wing, the undersides of primaries were also slaty gray with small white tongue tips on P6-8. Extended wing also showed a broad white trailing edge along the secondaries. These features are visible in the attached photos. Legs were not directly observed but two attached photos of the bird flapping its wings show the uppermost portion of the leg above the water, revealing a pale pink color. ID as Slaty-backed Gull based on overall size compared to LBBG, Herring Gull, and Great Black-backed Gull, distinctive wing pattern, bill shape and size, and apparent pink legs.

Technical information

Model

Canon EOS-1D X Mark II

Lens

EF600mm f/4L IS II USM +2x III

ISO

800

Focal length

1200 mm

Flash

Flash did not fire, auto

f-stop

f/8.0

Shutter speed

1/640 sec

Dimensions

1500 pixels x 1000 pixels

Original file size

1.1 MB